Help needed with my new build

Looks ok... What is your GPU? Impossible to say without GPU info.

EDIT: Is this your PSU? "Spyre SP ATX 600w Rocketeer IV"? It's a pretty crappy PSU....
http://techgage.com/article/spire_sp-atx-600w_power_sup...

EDIT: Totally missed it. Video card - Sapphire Vapor-x HD 5870 1GB

And the PSU?

You where right, that's the one. http://techgage.com/article/spire_sp-atx-600w_power_sup...

It could be the PSU... The article says it's basically a 450w, no name PSU. Do you have another PSU you can test with?

Unfortunately not, but I guess I gonna need one anyhow, right?
I also have in plan a crossfire in the near future. Can you recommend a good PSU for that please?

Well for crossfire 5870's and your system, I think 750w should be adequate. You might be able to get away with 650w, but let's not take chances.

With that in mind, I have several here that would be great. Let's go in order of price.

Antec Earthwatts 80+ 750w semi modular $90
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
026&cm_re=750w-_-17-371-026-_-Product

Corsair TX V2 750w 80+ bronze non modular $110
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

PC Power & Cooling Silencer MK II 80+ Silver non modular $120
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

XFX PRO 750w 80+ silver semi modular $130
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

Corsair HX 750w 80+ silver FULLY MODULAR $140
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

Seasonic X 750 80+ GOLD fully modular $160
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

Now let's talk over them.

MODULAR VS NON MODULAR
Modular just means you get to pick and choose the cables you need, which reduces clutter and improves airflow.

80+ RATINGS

80+ certified means it will deliver wattage at 80% efficiency.

80+ bronze is the standard. I believe it is ~82%?

80+ silver is about ~85%

and 80+ gold is ~87% and up.

I personally don't think it matters, as long as it's 80+.

My pick would be the antec Earthwatts, it's semi modular and 80+ for $90. A very good power supply.

If I had a bit more money I would step up to the Corsair HX. It's fully modular, and higher efficiency.

For non modular, the Silencer MK II would be my pick without a doubt.

Hope that helps!

I can get one of these faster from a shop here.
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
I'll probably go with the 850W one, they are virtually the same price. Or do you think the 950W might be a better choice in the long run (for future upgrades)?

If the modularity is worth it, go 850HX.

And NO, noooo need for the 950w. The only way I could see a 950w is GTX 580's in SLI with a 990x or something. The 850HX is a very high quality unit.

Thanks alot Striker, I'm greatfull for your help.
Cheers

Ok. Bought an 850AX in the end. All good and dandy, but I still get the crashes ...
Any suggestions?

I used to have the same kinda of crashes. Make sure your video drivers are up-to-date and run memtest on the RAM. You never know if you have a bad module. I did and never even knew it because only games push the memory. Other apps didn't cause the same kinds of issues. Hope that helps.